1. Field of the Invention
The present invention relates to a driving apparatus which is favorably used for driving a lens or the like in a mobile phone provided with a camera, a compact digital camera, etc.
2. Description of the Related Art
As the related-art driving apparatus in the above described technical field, there has been known a driving apparatus including an electromechanical conversion element which is expanded and contracted in an extending direction of a given fiducial line, a driving shaft which is fixed to one end of the electromechanical conversion element in the extending direction of the given fiducial line, a driven body which is frictionally engaged with the driving shaft, and a holder for holding the other end of the electromechanical conversion element in the extending direction of the given fiducial line (See JP-A-2002-142470, for example).
In the driving apparatus of this type, a driving pulse having a sawtooth waveform is inputted to the electromechanical conversion element, whereby the electromechanical conversion element is deformed in a state where its expansion speed and contraction speed are different from each other. When the electromechanical conversion element is deformed at a low speed, the driven body rests still with respect to the driving shaft by friction force, and on the contrary, when the electromechanical conversion element is deformed at a high speed, the driven body moves with respect to the driving shaft by inertia. Therefore, by repeatedly inputting the driving pulse having the sawtooth waveform to the electromechanical conversion element, it is possible to intermittently move the driven body at a small pitch.
However, in the driving apparatus as described above, the other end of the electromechanical conversion element in the extending direction of the given fiducial line is fixed to the holder. For this reason, there is such a problem that the holder resonates with the expansion and contraction of the electromechanical conversion element, and the driven body will not be reliably moved. In order to solve such problem, an art of holding the electromechanical conversion element from lateral sides with respect to the extending direction of the given fiducial line is advantageously employed (See JP-A-2007-74889, for example).
However, in the driving apparatus which employs the art of holding the electromechanical conversion element from the lateral sides with respect to the extending direction of the given fiducial line, there is such anxiety that the adhesive for holding the electromechanical conversion element by the holder may flow out to the moving region of the driven body on the driving shaft, and as the results, the movement of the driven body may be hindered.